Answer:
The correct answer is 84º.
Explanation:
The triangle presented is an isosceles triangle and we can determine this because we were given the measurements of two of its sides, and these are exactly the same.
The <em>ED</em> side measures 5 and the <em>EF </em>side also measures 5.
Now let's see, we only have the measure of one of its angles. The angle D with 48º.
But by definition, an angle that is opposite the sides whose measurements are equal must measure exactly the same.
Therefore, we already know that angle <em>F</em> will also measure 48º.
Having two of the angles measured, we only need to find the measure of the angle<em> E</em>. And for that we have to remember that all the internal angles of a triangle add up to a total of 180º, therefore you just have to make a difference:
D + F + E = 180º
48º 48º + E = 180º
E = 180º - 48º - 48º
E = 84º
The correct answer is 84º.
